/*
 * $AIST_Release: 0.9.0 $
 * Copyright 2011 Information Technology Research Institute, National
 * Institute of Advanced Industrial Science and Technology
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *    http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package util

import java.io.File
import java.io.FileOutputStream
import java.io.FileInputStream
import java.io.BufferedInputStream
import java.util.zip.ZipEntry
import java.util.zip.ZipOutputStream

object Zip {
  /**
   * Compresses with zip format.
   */
  def encode(top: File, files: List[String], zipfile: File): Unit = {
    val buf = new Array[Byte](1024)
    val zos = new ZipOutputStream(new FileOutputStream(zipfile))
    val topAPath = top.getAbsolutePath()
    val pos = topAPath.length + 1 // + 1 for "/"

    def encodeImpl(files: List[File]): Unit = {
      files.foreach { f =>
        if (f.isDirectory) {
          encodeImpl(f.listFiles.toList)
        } else {
          assert(f.getAbsolutePath().startsWith(topAPath))
          assert(f.getAbsolutePath.charAt(pos-1) == '/')
          assert(f.getAbsolutePath.charAt(pos) != '/')
          val fn = f.getAbsolutePath.substring(pos)

          val ze = new ZipEntry(fn)
          zos.putNextEntry(ze)
          val is = new BufferedInputStream(new FileInputStream(f))
          try {
            while ({
              val len = is.read(buf)
              if (len >= 0) {
                zos.write(buf, 0, len);
                true
              } else {
                false
              }
            }) {}
          } finally {
            is.close();
          }
        }
      }
    }

    val fs = files.map { new File(top, _) }
    try {
      encodeImpl(fs)
    } finally {
      zos.close()
    }
  }
}
